when i built mine i dug some of the foam out of the floor of the fuel tank compartment and put my flat battery under the tank. also i had a norvel .25 b.b. on mine and the cg came out good. beware! the sunrise is a handful to fly even for experienced flyers . that small wing has high wingloading it does not float down for a landing and it's high speed and small size means you will have to stay right on top of it!........good luck!
ORIGINAL: duttonflyer
Guys I have a .25 size sunrise that I have had built for awhile now but the cg is totally off from what the book says (the book says 2 1/4" +- 1/4 from the leading edge at the center section of the wing). I don't want to pile it up on the first flight because of improper setup. The model is setup with all standard 3004 futaba servoes a custom battery pack that I made to fit this little thing and an older K&B .20 that I had . My problem is that it is way tail heavy I added every lead weight I had for setting cg (about 7.5ozs.) around the firewall and it still didn't come out right. Where should the cg be and where should i set it from? That much extra weight seems excessive to me on such a little plane. The sunrise is only my third plane that ive built so i'm not very knowledgable yet. If anyone has experience with these planes and can help I would greatly appreciate it thanxs.